Emulsion
A dispersed two-phase system, i.e., an intimate mixture of two liquids that are (immiscible) under normal conditions, whereby one phase is dispersed in the other I the form of fine droplets.
Dispersed phase
Continuous phase
The dispersed droplets
The medium in which the droplets are dispersed
Two types of simple emulsion:
a) water in oil (w/o)
b) oil in water (o/w)
The stability of an emulsion depends on: ¨ degree of division of the inner phase ¨ quality/ stability of the interfacial film ¨ viscosity of the outer phase ¨ ratio and specific weight of the volumes of the two phases
Emulsifiers
- Substances which reduce the surface tension at the interface of two normally immiscible
phase, allowing them to mix and form an emulsion
- Surface-active agents
- Surfactant
Functions of emulsifiers
1)To promote emulsion stability, stabilize aerated systems, and control agglomeration of fat globules
2)To modify texture, shelf life, and rheological properties
3)To improve the texture of fat- based foods
How does emulsifier work?
They have both:-
- a polar group with an affinity for water (hydrophilic), and
- a nonpolar group with an affinity for oil (lipophilic)
Types of emulsifier: - nonionic - anionic - cationic - amphoteric
Emulsifiers
HLB- expresses the balance of size and strength of the hydrophilic and the lipophilic groups on the emulsifier.
HLB of 3-6: a good w/o emulsifier; (lipophilic)
HLB of 7-9: a good wetting agent; can be used for w/o or o/w emulsifiers
HLB of 10: a good o/w emulsifier; (hydrophilic)
A dispersed two-phase system, i.e., an intimate mixture of two liquids that are (immiscible) under normal conditions, whereby one phase is dispersed in the other I the form of fine droplets.
a) water in oil (w/o)
b) oil in water (o/w)
The stability of an emulsion depends on:
¨ degree of division of the inner phase
¨ quality/ stability of the interfacial film
¨ viscosity of the outer phase
¨ ratio and specific weight of the volumes of the two phases
Emulsifiers
- Substances which reduce the surface tension at the interface of two normally immiscible
phase, allowing them to mix and form an emulsion
- Surface-active agents
- Surfactant
Functions of emulsifiers
1)To promote emulsion stability, stabilize aerated systems, and control agglomeration of fat globules
2)To modify texture, shelf life, and rheological properties
3)To improve the texture of fat- based foods
How does emulsifier work?
They have both:-
- a polar group with an affinity for water (hydrophilic), and
- a nonpolar group with an affinity for oil (lipophilic)
Types of emulsifier:
- nonionic
- anionic
- cationic
- amphoteric
Emulsifiers
HLB- expresses the balance of size and strength of the hydrophilic and the lipophilic groups on the emulsifier.
HLB of 3-6: a good w/o emulsifier; (lipophilic)
HLB of 7-9: a good wetting agent; can be used for w/o or o/w emulsifiers
HLB of 10: a good o/w emulsifier; (hydrophilic)